The invention relates to a light irradiating apparatus provided with an excimer lamp including a high voltage side electrode configured to be cooled by a cooling medium such as pure water.
A manufacturing process of, for example, a semiconductor device or a liquid crystal panel involves optical ashing treatment of a resist or dry cleaning treatment with respect to a glass substrate or a silicon wafer. Also, a nanoimprint method entails optical ashing treatment of a resist adhering to a patterned surface of a template. Furthermore, in a manufacturing process of a printed circuit board, wiring board materials are subjected to desmear treatment or surface roughening treatment of an insulating layer.
In such treatment, a light irradiating apparatus provided with an excimer lamp has been used. Moreover, for example, in desmear treatment of wiring board materials, a large-output light irradiating apparatus has been desired, seeking for shortened treatment time.
In such a large-output light irradiating apparatus, when an excimer lamp is lit, temperature of the excimer lamp increases to a considerably high temperature, causing deterioration in luminous efficiency. Accordingly, cooling of the excimer lamp is desirable. Thus, Japanese Unexamined Patent Application Publication No. H04(1992)-301357 discloses a light irradiation apparatus in which a high voltage side electrode of the excimer lamp is cooled by allowing a cooling medium having low electric conductivity to be in direct contact with the high voltage side electrode. The cooling medium may be, for example, pure water or the like.